利用相位多普勒粒度分析仪(PDA)实验台测量了双流体喷嘴出口速度与粒径分布,利用得到的速度与粒径数据对江苏某生物质电厂进行小水量脱硫废水蒸发的数值模拟,着重研究了液滴粒径以及烟气中水蒸气的体积分数对液滴蒸发过程的影响.PDA 实验结果表明,该双流体喷嘴在特定气液比条件下出口粒径均小于100μm.应用离散相模型与随机轨道模型,利用Rosin-Rammler分布模拟喷雾液滴分布范围(0~100μm).模拟结果表明,粒径低于100μm 的液滴能够完全蒸发,液滴粒径越小,完全蒸发时间越短,液滴经历的平稳吸热时间越短.随着粒径的增加,液滴完全蒸发时间增幅变大.随着烟气中水蒸气体积分数增加,液滴蒸发速率变缓,液滴开始蒸发的时间延长,且体积分数越大,出口未蒸发完全的液滴直径越大,但出口液滴粒径增大的幅度在减小.%PDA was used to measure the velocity and diameter distribution of two-fluid spray nozzle. Experimental data of velocity and droplet diameter were applied to simulate the desulfurization waste evaporation in one biomass power plant in Jiangsu. Simulation was focused on the droplet diameter and water vapor volume fraction in flue gas which affected the evaporation progress. Results of PDA experiments showed the diameter of two-fluid spray nozzle under special gas-liquid ratio was less than 100μm. Discrete phase model,stochastic trajectory model,and Rosin-Rammler distribution was used to simulate the distribution of spray around(0—100μm). The simulation showed that with the diameter of droplet getting smaller, the complete evaporation time of droplet became shorter and the steady heat absorption time of droplet got shorter. Furthermore, the bigger particle diameter was,the larger complete evaporation time increment of droplet. In terms of water vapor,with its volume fraction in flue gas getting larger,the speed of evaporation slowed down,and the starting of droplet delayed. In addition,the greater the volume fraction was,the larger Sauter mean diameter at exit,but amplitude of increasing in diameter was reduced.
展开▼
